Davis, a former Special Forces soldier who left the military in 2003, shot the men in what he described as an attempted armed robbery in the eastern city of Lahore as they approached him on a motorcycle.

Munter said the U.S. Department of Justice has opened an investigation into the incident involving Davis, who shot dead two Pakistanis in the eastern Punjab city of Lahore on January 27 after what he described as an attempted armed robbery.

On Thursday, Mr. Kyl said in a statement that until the explosion in Georgia - which he called an "attempted bombing of the U.S. Embassy" - was resolved, efforts to reset relations with Russia should be halted.